Basic Help
Conversion Chart
Liquid Measurements
1 pint = 2cups = 32 tablespoons = 96 teaspoons = 16 fl oz.
Weights
1lb = 454 grams, 1 oz. = 28.37 grams, 16 oz. = 1lb
Measurements by Volume (Using Water)
1 gallon = 231 cubic inches = 4 quarts = 8 pints
133.37 ounces = 8.3356 pounds = 3.785 liters
1 cubic foot = 7.48 gallons = 1728 cubic inches
62.4 pounds/ water (Specific gravity of water 1.0)
Pressure Measurements
Positive Pressure (pounds per square inch): 0 to 100 psi
Negative Pressure (vacuum): 0 to 30 inches of mercury
Calculating Resin Amounts
To find the amount of resin mixture needed to fill the mold cavity, first fill the cavity with water and weigh it. Take the weight of the water multiplied by the specific gravity of the resin mixture and you will have the amount of resin mixture required.
Calculating Foam Amounts
For foam parts take the weight of water in relationship to cubic foot of water---1 cu/ft = 62.4 lbs. Multiply the cubic foot by pound density of foam. This will give you the amount to start with to fill the cavity with foam. Over-pack by 5% to thicken the cell structure and create a good smooth skin.
EXAMPLE: How much foam is needed if you are using a 12# density foam and need to fill a cavity that has a water weight of 48 lbs ?
STEP 1 48# = .769/cubic ft (48 divided by 62.4 = .769 cubic ft).
STEP 2 .769 x 12# density foam = 9.228 lbs. So you need 9.228 lbs of 12# density foam to fill the mold cavity.
STEP 3 9.228 x 1.05= 9.689 (1.05 is 5% more material than needed)